Typically, conveyor rollers are mounted along opposite sidewalls of a conveyor. The rollers include shafts which extend longitudinally outwardly from each end of the roller and which are received by apertures or slots in the sidewalls of the conveyor. These shafts are often non-circular, such as hexagonal shaped, such that rotation of the shafts relative to the sidewalls is substantially precluded when the shaft is received by a correspondingly shaped slot or hole in the sidewall.
A motorized roller typically includes a motor within the cylindrical portion of the roller, which causes relative rotation between the shaft portions and the cylindrical portion of the roller. Accordingly, when the shafts are secured to the sidewall of the conveyor, actuation of the motor within the roller causes the cylindrical portion of the roller to rotate. Because of the torque generated when the motorized roller is actuated, the shaft, which is submitted to the same torque, tends to rotate in the opposite direction from the cylindrical portion of the roller, such that the sides of the non-circular shaft repeatedly impact the sides of the corresponding slot or hole in the sidewall, thereby preventing rotation of the shaft. This repeated impact and relative movement may cause the edges of the shaft or of the hole or both to become worn or rounded over time, which leads to a looser fit of the shaft within the opening. Any looseness between the shaft and opening further results in squeaks or other noises and/or vibrations of the conveyor when it is operated. This eventually may result in greater maintenance costs and even loss of function, since the roller and/or the entire sidewall may have to be replaced when the wear and tear to the shaft and/or the opening in the sidewalls becomes excessive. Motorized rollers are typically implemented with a set of non-driven or slave rollers and may be interconnected with the slave rollers by a plurality of bands or O-rings, such that rotation of the cylindrical portion of the motorized roller causes a corresponding rotation of the slave rollers.
Because of the torque generated by the motorized rollers, it is generally preferred that the shafts be inserted through openings or holes and not placed into slots whereby only a portion of the sidewall would contact and restrain the shafts. The openings in the sidewalls are desired to be as close to the diameter of the shaft of the roller to provide as tight a fit as possible between the roller shaft and the sidewall opening. However, such a tight fit may make it difficult to install the roller to the sidewalls. In some applications, the shafts may be spring loaded, such that the shaft may be pushed longitudinally inwardly into the roller to align the roller shaft with the opening in the conveyor sidewall and then released to allow the shaft to extend outwardly through the opening, thereby securing the shaft to the conveyor sidewalls.
In order to improve upon the wear and tear and noise of the systems, one proposed device has implemented a tapered end to the shafts of the roller. When the tapered shafts are released, the spring loading of the shafts maintains a tight fit in the opening, since the opening is of a smaller size than the largest diameter of the tapered portion of the shaft. While this at least initially provides for a tighter fit between the roller shaft and the opening in the sidewall of the conveyor, over time the shaft and/or opening may wear and allow the shaft to extend further into the opening. The shaft may eventually extend outwardly to a point where the spring is no longer in compression, such that the shaft is no longer held tight to the opening in the sidewall. Therefore, while this device may delay a loose fit of the shaft within the openings, this does not avoid the requirement of eventually having to replace or repair the sidewalls of the conveyor and/or the roller as they become worn.
Therefore, there is a need in the art for an adjustable mounting structure for receiving and substantially securing the shaft ends of conveyor rollers, especially motorized conveyor rollers, which overcomes the shortcomings of the prior art.